Synthesis, crystal structures and Hirshfeld analyses of phosphonothioamidates (EtO)₂P(=O)C(=S)N(H)R (R = Cy, Bz) and their coordination on CuI and HgX₂ (X = Br, I)

Abstract

The phosphonothioamidates (EtO)₂P(=O)C(=S)N(H)R (L1 R = Cy; L2 R = Bz) have been prepared by nucleophilic addition of K[(EtO)₂P(=O)] to R–N = C=S and crystallographically analyzed. Both compounds are associated pairwise through strong intermolecular N–H···O bonding giving rise to 10-membered supramolecular macrocycles. This intermolecular bonding has also been studied by Hirshfeld analysis of L1 and L2. Complexation of L on CuI in MeCN solution affords the dinuclear rhomboid-shaped thione complexes [{Cu(μ₂-I)₂Cu}(η¹-L)₂] (1a,b). Crystallographic characterization of 1a reveals that L1 is ligated exclusively via the thione function to the trigonal Cu(I) centers, which are interconnected through a short Cu–Cu bond of 2.6207(4) Å. In the solid state, individual dimeric complexes are associated through intermolecular N–H···O bonding generating a supramolecular 1D ribbon. The dinuclear complexes [{XHg(μ₂-X)₂HgX}(η¹-L)₂] (2a X = Br, L = Cy; 2b X = Br, L = Bz; 2c X = I, L = Bz) were formed by stoichiometric addition of L to HgX₂. The molecular structures of 2b and 2c have been elucidated by X-ray diffraction studies, which show that individual complexes are connected through intermolecular N–H···O bonding generating a supramolecular 1D ribbon. Treatment of L1 with two equivalents of HgBr₂ produces the tetranuclear compound [Hg₄Br₈(κ¹-L1)₂] 3, whose unusual bromide-bridged architecture has been elucidated by X-ray crystallography.

GRAPHICAL ABSTRACT

Keywords:

• Phosphonothioamidates
• crystal structure
• Hirshfeld analysis
• coordination chemistry
• supra-molecular bonding
• copper (I)
• mercury (II)

Acknowledgments

This work was supported by the Ministry of higher education and scientific research of Tunisia and by the CNRS. We thank Ms. Stephanie Boullanger for recording the NMR and ATR-IR spectra. L. B. thanks the Fonds der Chemischen Industrie (FCI) for a Chemiefonds Fellowship.